Peach Tree Has Many, Many Holes

We discovered lots of holes in some branches of our peach tree. I have never seen these types of holes before in any tree. The hole narrows down like a sharpened pencil tip or ice-cream cone. Our peach tree is dead on one side. The other side is green and has nice leaves and some flowers just starting to come out. What is this? I want to take care of this right away but don't know where to start. I really love this tree. It gives nice peaches.